Some automatic trans cranks didn't have pilot bushings hole needed to install the manual trans input shaft's pilot bushing.

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Joshua

Well because my grandpa came up with this idea that it has a pilot bushing in it, and thats why the new TC wont fit. I trust my grandpa, and I appreciate what he does, but he somehow came up with this idea that useing the old TC will screw up the new trans and start leaking. I don't see how thats possible, when it was fine on the old trans. Now he says were going to have to take the crank out and have it machined We got into a big arguement over that one.

What exactly is the pilot bushing for?

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'74 Duster 225 Super Six w/904
14" Cragar SS wheels

Pilot bushing holds the input shaft of a manual transmissin, in line with the crankshaft.

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Part of Tyrde-Browne Racing

The image below is the end of a SL6 crankshaft.

Starting at the outer edge:
We have the flange which is the large, outer surface, with the bolt hols in it.

Next is the "shoulder" which is the raised ring that centers the flex plate or the flywheel to the crankshaft's centerline.

Moving inward, we see the counter-bore. This centers the "nose" (hub) of an automatic transmission's torque converter.
This counterbore is 1.555 diameter 1960 to 67 and increased size to 1.812, in 1968 to accept a later / larger converter hub... needed for a bigger auto trans input shaft.

Next we see the pilot bushing installed into the pilot bushing hole. This is the small hole in the center, with the brass "sleeve" on the outside edge. This is to support a manual transmission's input shaft. it does not do anything for the automatic transmission.
DD

So the bushing would have nothing to do with it, wether it is installed or not? So why would one converter (the old) have so much play, and the other one (new) not? Maybe the new converter is made wrong?

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'74 Duster 225 Super Six w/904
14" Cragar SS wheels

Apologies to your Grandfather, but the presence or absence of the pilot bushing has nothing to do with the torque converter.

You need to measure the size of the large hole in the back of the crank. You need to measure the diameter of the nose on the torque converter. Report back with both measurements. You need to count the splines on the transmission input shaft. That's the smaller shaft, the one that turns. Check both transmissions. Report your findings.

Obviously a large nose torque converter will not fit into an early crank. Also, a large nose torque converter will not engage the smaller, earlier trans input shaft.

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Joshua

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'74 Duster 225 Super Six w/904
14" Cragar SS wheels

In the Parts for Sale section there is a thread about some conveters with the small, pre-68 snout and the 68+ splines to mate a late transmission to an early crankshaft. If you're still having problems this *might* be the solution for you.

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David Kight
'62 Valiant Signet, White
'98 Dodge Dakota
'06 Jeep Liberty

Growing older is unavoidable but growing up is strictly optional.

Well, we got the trans back in, it turns out there was a little mis-communication, my grandpa ment grinding the ridge off the torque converter snout, and not the crank... Oh well, we ground down the snout, and that seemed to work. Now I just need to find a day off of work to finish it up. I can't wait! Im like a spaz on crack that hasn't got his fix in a couple of weeks

With that new trans, a shift kit, the center console, new tires, etc. this thing is going to be fun and ready for some shows this summer! Expect some new pics in the next week or so, the weather is getting warm, and this thing has a new look, once I get it clean...

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'74 Duster 225 Super Six w/904
14" Cragar SS wheels